Regulating system



Patented Nov. 20, 1945 REGULATING SYSTEM Stanley J.

Westinghouse Mikina, Wilkinsburg, Pa., assignor to Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application March 21, 1944, Serial No. 527,450

12 Claims.

This invention relates, in general, to regulating systems and, in particular, to position and tension regulating systems.

.An object of this invention is to provide a regulating system for controlling the direction and speed of operation of a motor.

Another object oi this invention is to provide in a regulating system for controlling the direction and speed of operation of a motor for effecting a velocity response to compensate for time delays inherent in the regulated system.

Other objects of this invention will become apparent from the following description when taken in conjunction with the accompanying drawing in which Figure 1 is a diagrammatic illustration of the apparatus and circuits embodying the teachings of this invention as applied to a tension regulator, and

Fig. 2 is a diagrammatic illustration of the apparatus and circuits embodying the teachings of this invention as applied to a position regulator. I

Referring to Fig. 1 of the drawing, this invention is illustrated by reference to the winding of a wire III on an irregularly-shaped mandrel 12 from a supply reel 14. The mandrel i2 illustrated is of rectangular shape such as is employed in industry for the winding of coils for transformers or the like, and is disposed to be driven at a predetermined speed by any suitable motor it. The motor I6 comprises an armature winding [8 and a field winding 20 which are connected to suitable sources of supply-(not shown).

As illustrated, a direct current reversible motor 22 is provided for cooperating in controlling the speed of the supply reel i4 and the tension of the wire between the reel i4 and the mandrel l2. The motor 22 comprises an armature winding 24 and a field winding 28, the

field winding being separately excited from any suitable source of power (not shown). The supply reel 14 is carried on the armature shaft 28 and is, therefore, responsive to the speed and direction of operation of the motor 22.

In order to control the speed and direction of operation of the motor 22, the armature winding 58 is connected to a suitable source of direct current as represented by the positive and negative signs through a resistor bridge circuit. As illustrated, one leg of the resistor bridge circuit'comprises resistors 30 and 32 connected between the positive terminal of the dithe negative terminal of the direct-current source and the armature l8, respectively. The other leg of the resistor bridge circuit comprises a fixed resistor 34 and an adjustable resistor 36 connected between the positive terminal of the direct-current source and the armature I8 and a fixed resistor 38 and an adjustable resistor 40 connected between the negative terminal of the direct-current source and the armature [8, respectively.

In order to adjust the resistors 36 and 40 to control the number and sections thereof which are connected in series circuit relation with the armature l6 and thereby control the direction of the flow of direct current through the armature, a pair of primary control devices 42 and 44 is provided and disposed to be operated in a predetermined manner. Each of the primary control devices 42 and 44 is formed of a plurality of elongated conducting leaf spring members 48 having one end of each member secured in fixed spaced relation to each other and extending through suitable insulating means such as the block 48, so that their free ends are self-biased against a sloped stop 50 of insulating material. The contact members 52 carried on the free ends will be in spaced relation 'to each other when the free ends of the conducting members seat against the sloped stop 50. Each of the fixed ends of the stacks of conducting members is so connected by a conductor 54 to a different tap oi the resistors 36 and 40 that the conducting members of control devices 42 and 44, respectively are progressively connected to progressive taps of the respective resistors. An insulating driving member 56 is disposed to be actuated under predetermined conditions to effect a simultaneous progressive actuation of theconducting members of control devices 42 and 44 away from the sloped stops to simultaneously shunt the resistor sections of resistors 36 and 40 in a progressive manner. The driving member 56 may be mounted in any suitable manner and is normalhr biased away from the conducting members 46 as by the spring 58. The primary control devices 42 and 44 referred to hereinbeiore are disclosed and claimed in Patent No. 2,246,301, issued June 17, 1941, to C. R. Hanna et al. which is assigned to the assignee of this invention.

The driving member 56 of the primary control devices 42 and 44 is disposed to be actuated in accordance with the tension of the wire Ill between the suppiy reel I4 and the winding mandrel i2. As illustrated, the wire I0 is supplied rect-current source and the armature I8 and the mandrel I: by passing the wire over an idler pulley 80 which is carried in a substantially nonfriction manner at the end of an arm 82 which is mounted for pivotal movement. The other end of the arm 82 is fixedly mounted on a shaft 64 which extends between and through suitable brackets 56, only one 01' which is shown, the shaft 64 being disposed to be rotated therein. The brackets 66 are mounted on a base plate which carries arms 68, I and T2 thereon, the arms and 12 being provided with stop members l4 and 16, respectively, for limiting the extent of movement of the arm 62 whereas the arm 88 serves as the anchor point for sp n 78 which restralns the clockwise movement of the arm 62. In order to operate or move the driving member Eli-against the bias of spring 58, a cam 80 is carried on the rotatable shaft 64 disposed to engage the end of the driving member 56.

As illustrated, two frictionally actuated switch members 82 and 84 are disposed for operation by the rotation of shaft 84 into and out of engagement with the cooperating stationary contact members 86 and 88, respectively. The switch members 82 and 84 are carried by insulating blocks 90 and 92, respectively, each of which is provided with a central opening therein through which the rotatable shaft 64 projects. The central openings of the blocks 90 and 92 are large compared with the diameter of the rotatable shaft 64, the blocks 90 and 92 being biased into frictional engagement with the shaft 64 by springs 94 and 96, respectively. The stationary contact member 86 is connected by conductor 98 to the lead between the positive terminal of the direct-current source and one end of the fixed resistor 34 while its cooperating movable contact member 82 is connected by conductor Hill to the other end of fixed resistor 34. The stationary contact member 88 is connected b conductor 102 to one end of fixed resistor 25 and its cooperating movable contact member 84 is connected by conductor I04 to the lead between the negative terminal of the source of direct current and the other end of resistor 38. Thus when the contact members 82 and 84 are actuated to a circuit closing position, the fixed resistors 34 and 38 are shunted from the armature circuit to give a reduced resistance path for the current from the direct-current source. 4

The blocks 90 and 82 and the springs 94 and 96 are so selected that for a clockwise movement of the shaft 64, the contact members 82 and 84 are actuated into circuit closing position and are maintained in that position so long as the direction of rotation of the shaft 64 is unchanged, the

blocks slipping on the shaft 84 without damage thereto. In practice if the rotation of the shaft .64 should become reversed as will be explained more fully hereinafter, the contact members 82 and B4 are actuated to'a circuit opening position. In general practice the contact members 82 and 84 are actuated to give, in effect, a vibratory switching operation with their cooperating stationary contact members 86 and 88.

In operation, assuming that the wire it has been threaded over the idler'pulley to the mandrel I2, the arm 62 is normally seated against the stop 14 until the motors l6 and 22 are energized. With the arm 62 in this position the conducting members 46 of primary control devices 42 and 44 are seated against their cooperating 4 sloped stops 50 and all of resistors 40 and 36 are connected in series circuit with the armature winding 24 of motor 22. Thus when motors l6 and 22 are initially energized, the motor 16 tends to wind the wire In on the mandrel l2 whereas the motor 22 tends to wind the wire 10 on the reel [4. The latter operation of motor 22 is evident since with all of resistors 40, 38, 34 and 38 connected in circuit with the armature winding 24, the current flow through the armature is through the low resistance leg of the bridge circuit and may be traced from the positive terminal of the direct-current source through resistor 30, armature winding 24 and resistor 32 to the negative terminal of the direct-current source to eifect the operation of the motor 22 and the reel I 4 in a clockwise direction to tend to wind the wire ID thereon.

Since the mandrel l2 and reel H are operating in opposition, the tension applied to the wire In is increased to effect a rotation of the arm 62 and shaft 54 in a clockwise direction to operate the cam in a direction to actuate the driving member 55 to eflfect the gradual and progressive movement of the conducting members 48 away from the sloped stops 50 until a sufllcient number of sections of resistors 40 and 36 are shunted and the leg of the bridge circuit containing resistors 34, 36, 38 and 40 has less resistance than the leg containing resistors 30 and 32. When this happens the current flow through the armature winding is reversed to effect the operation of the motor 22 and the reel H in a counterclockwise direction.

' The speed of the reel i4 is controlled to maintain substantially constant tension on the wire l0, any variations therein being reflected by a movement of the arm 62 and a corresponding movement of the cam 80 to efiect an adjustment in the number of sections of resistors 40 and 36 which are shunted from the armature circuit and thereby control the speed of unwinding from the reel l4 or the reversal of the motor 22 to tend to wind the wire 10 on the reel.

For ideal operating conditions, the arm 62 is in the position illustrated intermediate the stops l4 and 16. However, as will be appreciated, there will be constant movement of the arm 62 in one or the other directions away from the intermediate position for as the mandrel i2 is turned, the irregular shape of the mandrel efiects a constant change in the wire velocity. Further if for any reason the wire on the mandrel 12 should become tangled, it is necessary to change the operation of the reel H from an unwinding operation to one tending to wind the wire thereon in order to maintain the tension and prevent further entanglement of the wire ill.

The circuits and apparatus discussed hereinbefore are satisfactory for tending to maintain the tension on the wire, being responsive to the positioning of the arm 62 as it varies with changes in the tension. However, the operation of the system responsive to the positioning of the arm 62 has an inherent time delay in effecting the required changes in the armature current, and the contact members 82 and 84 are, therefore, utilized for making a correction in the armature current in response to the velocity change or change in direction in positioning the arm 62 to anticipate the gradual corrective operation of the position responsive apparatus and circuits.

For example, as the tension on the wire 10 increases as described, the movement of the cam 80 and the operation of primary control devices 42 and 44 introduces an inherent time delay in effecting the change in the speed of the motor 22.

However. the increase in the tension eifects a rotation of the shaft 64 in the clockwise direction and the contact members 82 and 84 carried by the blocks 88 and 92, respectively, which are in frictional engagement with the shaft 64, are immediately actuated to their circuit closing position to immediately shunt resistors 34 and 38 from the armature circuit to increase the current flowing through armature winding 24.

With the contact members 82 and 84 in their circuit closing positions, current flows from the positive terminal of the direct-current source through conductor 88, contact members 88 and 82, conductor I88, the first lead 54 and the closed contact members 52 of primary control device 44, the unshunted part of resistor 38, armature winding 24, the first lead 54 and the closed contact members 52 of primary control device 42, the unshunted part of resistor 48, conductor I82, contact members 88 and 84 and conductor I84 to the negativeterminal of the direct-current source. By thus immediately shunting resistors 34 and 38, the armature current is so increased as to increase the speed of unwinding of reel I 4.

The contact members 82 and 84 are maintained in their circuit closing position as long as the direction of rotation of shaft 84 is unchanged .to effect a change in the speed of the motor in anticipation of the change which the cam 88 and primary control devices 42 and 44 will effect. As soon as the rotation of shaft 64 is stoppedor the direction of rotation is reversed, contact members 82 and 84 are actuated to their circuit opening positions and the control of the speed and direction of operation of the motor 22 is obtained through the cam 88 and the primary control devices 42 and, 44. In practice, the position of arm 62 is changing at all times so that the contact members 82 and 84 vibrate into and out of circuit closing position depending upon the direction of change of rotation of the shaft 84, and by cooperating with the position responsive cam 88 and primary control control devices 42 and 44, a very close control of the tension of the wire I8 is obtained.

From the foregoing description of the operation of the regulating system. it is evident that varia-' tions in the motor current due to the action of the frictlonally operated contact members 82 and 84 are such as -to produce variations in the motor torque that oppose changes in the velocity of the motor 22 and associated reel I4 thus giving a damping effect similar to that produced by a brake disposed to alternately engage and disengage the armature shaft 28] The change in metor torque due to the action of the frictionally operating contact members 82 and 84 in alternately connecting and shunting fixed resistors 34 and 38, respectively, from the armature circuit is a fixed value independent of the motor velocity or idler pulley shaft velocity since the contact members 82 and 84 are moved immediately into and out of engagement with their cooperating fixed contact members 88 and 88, respectively, depending upon the direction of the velocity change of the pulley shaft 84. This non-linear velocity respouse is analogous to the rate of change response in alinear system and thus serves approximately to compensate for time delays in the regulating system. In a regulating system responsive to changes in position such as that described, the effect of time delays between the appearance of an error and a subsequent change in motor torque to correct this error is to cause the change in corrective motor torque to have a component in phase or in the direction with the motor velocity, thus tending to excite and maintain hunting oscillations of the system. It'ls thus seen that the frictionally-operated contactmembers 82 and 84 effect a change in the correctivemotor torque that has i a component 'out-of-phase, or opposing the direction ofthemotorvelocity thus compensating for the in-phase component due to the system time-delays. The cooperating apparatus and circuits of the system described effectively maintains a substantially constant tension on the wire I8 andeliminateshuntingoscillations in the regulated system.

In the embodiment of this invention illustrated in Fig. 2 the speed-and directionof operation of a positioning motor I88 isso controlled that it operates-to position an'object such as a gun (not shown) inresponseto areference position. The motor I88 comprises an armature winding I88 and a separately excited field winding H8, an armature shaft I I2 being provided'for carrying the object to be positioned and for connecting the motor through thegea rs I I4 and a diIIerential H6 to-a-referencepositiom In this instance the 'referenceposition is :manuallycontrolled as represented by the handle H8 shown on the differential. By connecting the motor I88 to one side of the differential and the. manual control H8 to the other side of the control, the output shaft I28 of the differential moves in accordance with the diiferencein speed'and direction of operation of the motor I86 and the. reference object H8.

The motor I88 has its armature winding I88 connected across the armature winding I22 of a generator I24 which'is driven by a motor I28. The generator I24 i provided with two field windings I28 and I38 connected differential for controlling the output of the generator. and consequently the speed anddirectlon of the positioning motor I88. As illustrated, eachof thefield windings I 28 and I38 is connected across a directcurrent source represented by-the positive and negative signs, a fixed resistor I32'and an adjustable resistor I34 being disposed. to be connected in circuit with field winding I28-and a fixed resistor I36and an adjustableresistor I 88 being disposed to be connected in circuit with the field winding I38.

The adjustable resistors I34 and I38 are formed of a plurality of sections, the taps of which are connected by leads I48 to the fixed ends of conducting leaf spring members I42 of primary control devices I44 'and I48, respectively. The primary control devices-l44 and I48 are identical to primary control devices 42 and 44 employed in the embodiment of Fig. 1 but in the embodiment of Fig. 2, the primary control devices are disposed in opposition and are provided with acommon driving member I48. The driving member I48 is so disposed between the primary'control devices m and us that for a balanced condition an equal number' of conducting members I42 of each of the primary control devices are actuated to circuit closing position and as the driving member I48 is actuated to close more of the conducting members I42 of one of the primary control devices a simultaneous release or opening of an equal number of the contact members I58 of the other primary control device is obtained. The driving member I48 is actuated by the cam I52 carried on the end of the rotatable shaft I28 against the bias of spring member I54.

As in the embodiment of Fig. l, the system of Fig. 2 also utilizes a switch responsive to the direction of rotation of the rotatable shaft, 8. movable contact member I58 being carried by the block I58 positioned on and maintained in frictional engagement with the shaft I20 by the spring I60 for vibratory engagement with a pair of oppositely disposed contact members I62 and I64.. The movable contact member I56 is connected by conductor I66 to the positive terminal between the ends of resistors I32 and I36 whereas the contact members I62 and I64 are connected by conductors I68 and I10, respectively, to the cuits, the field excitation and output of the gen-' erator I24 is zero and the motor I06 remains stationary.

If the reference object H8 is moved, as by turning it counterclockwise with respect to the shaft I20, the shaft I20 is immediately rotated, the rotation being the differential between the reference object movement and the rotation of the motor shaft II2 as imparted to the differential II6 through the gears II4 to effect a movement of the cam I52 counterclockwise with reference to the shaft I20 whereby the bias of the spring I54 forces the driver member I48 is a direction to progressively release the conducting members of primary control device I44 and to progressively drive more of the conducting mem-' bers of primary control device I46 into engagement thereby increasing the resistance in circuit with the field winding I28 and decreasing the resistance in circuit with the field winding I30. Forgetting for the time being the effect of the friction operated contact member I56, it is seen that the change in the resistance by reason of the operation of primary control devices I44 and I 46 increases the current flowing in field winding I30 to cause the generator I24 to supply current to the armature I08 of motor I06 to cause it to drive the object (not shown) carried by the armature shaft II2 .to a position corresponding to the position of the reference object II8. As the motor I06 is operated, the shaft I20 responds to the differential of movement between the motor shaft H2 and the now stationary reference object II8 to reverse its direction of rotation to actuate the cam I52 in the opposite direction to operate the driving member I48 to release the conducting members of primary control device I46 and move those of device I44 to circuit closing position to progressively decrease the excitation of generator I24 and consequently the speed of motor I06 until-the field windings I28 and I80 are again balanced and the motor I06 is stopped.

As the reference object H8 is moved and the shaft I20 is rotated, the movable contact member I56 is actuated into engagement with contact member I62 or I64 depending upon the direction of rotation of the shaft I20. If the movement is as described hereinbefore in a counterclockwise direction about the shaft I20, then the contact member I56 is carried into engagement with contact member I64 to immediately shunt the resistor I36 from circuit with the field winding I30 and thereby effect an immediate increase in the excitation of the generator I24 to effect an accelerated operation of the motor I06. Contact member I56 remains in its circuit closing position with contact member I64 as long as the shaft I20 is rotated or until the direction of rotation of shaft I2 0 is reversed, to give an accelerated operation of the motor I06 in anticipation of the gradual correction obtained by operation of the primary control device I46. 7

It will be appreciated that if the movement of the reference object I I8 is in a clockwise direction with reference to the shaft I20 that primary control device I44 will operate to shunt progressive sections of resistor I34 and primary control device I46 will function to add sections of resistor I38 to the respective field circuits of field windings I28 and I30, respectively, to so change the output of generator I24 as to reverse the current flowing through the armature I08 of motor I06 to move the object (not shown) to a position complementary to that of the reference object II8. Simultaneously therewith, the contact member I56 is actuated to engage contact member I62 and thereby immediately shunt resistor I82 from circuit with the field winding I28 to accelerate the operation of the motor I06. As in the previous case, the contact member I56 is maintained in engagement with contact member I62 as long as the shaft I20 is rotated or until the direction of rotation of shaft I20 is changed.

In both of the embodiments described hereinbefore the regulating systems are sensitive to changes giving a sensitive control of the operation of the driving motor. By utilizing the velocity responsive frictionally actuated switches to give a nonlinear velocity response, a superior regulating system is obtained since such velocity or direction responsive control eifectively compensates for time delays inherent in the position regulating system.

While this invention has been described with reference to specific embodiments, it is of course not to be limited thereto except insofar as is necessitated by the scope of the appended claims.

I claim as my invention:

1. In a regulating system, in combination, a motor to be controlled, a direct-current source for operating the motor connected across the motor armature, a plurality of circuits connected to the direct-current source for controlling the operation of the motor, means provided in each of the circuits connected to the direct-current source for controlling the fiow of current in the circuits to effect a reversal of the motor armature, and means connected to the motor responsive to operating conditions for effecting the operation of the controlling means for controlling the direction of flow of current through the armature.

2. In a regulating system, in combination, a motor to be controlled, 2. direct-current source disposed to be connected across the motor armature, a plurality of resistor circuits connected between the direct-current source and the motor armature, certain of the resistors of at least one of the resistor circuits being adjustable, means disposed for adjusting the adjustable resistors in a predetermined manner for controlling the flow of current in the plurality of resistor circuits to effect a reversal of the motor armature, and means connected to the motor responsive to operating conditions for effecting the operation of the adjusting means for controlling the direction of fiow of current'through the armature.

. 3. In a regulating system, in combination, a motor to be controlled, 2. direct-current source for operating the motor connected across the m0- tor armature, a plurality oi circuits connected to the direct-current source for controlling the operation of the motor, means provided in each of the circuits connected to the, direct-current source for controlling the flow of current in the circuits to effect a reversal of the motor arma ture, a member disposed for rotational operation in response to operating conditions of the motor, means responsive to movement of the rotatable member for effecting the gradual operation of the controlling means for controlling the direction and amount of current flowing through the motor armature, and meansresponsive to directional movement of the rotatable member disposedfor simultaneous operation with the gr drial operating means foreiiecting quick ini ial changes in the direction of flow of current through the motor armature.

'4. In a regulating system, in combination, a motor to be controlled, a direct-current source disposed to be connected across the motor armature, a plurality of resistor circuits connected between the direct-current source and the motor armature, certain of the resistors of at least one oi the resistor circuits being adjustable, means disposed for adjusting the adjustable resistors in a predetermined manner for controlling the flow of current in a plurality of resistor circuits to effect a reversal of the motor armature, a member disposed for rotational movement in response to operating conditions of the motor, means responsive to positional movement of the rotatable member for effecting the gradual operation of the adjusting means for controlling the direction oi flow of current through the motor armature, and means responsive to directional movement or the rotatable member disposed for simultaneous operation with the gradual operating means for eifecting quick initial changes in the direction of flow of current through the motor armature.

5. In a regulating system, in combination, a motor to be controlled, a direct-current source disposed to be connected across the motor armature, a resistor bridge circuit having adjustable resistors in one o! the leg thereof connected between the direct-current source and the motor armature, switching apparatus disposed for adjusting the adjustable resistors for controlling the flow of current in the bridge circuit to effect a reversal of the motor armature, a member disposed ior rotational movement in response to operating conditions of the motor, means responsive to positional movement of the rotatable member for effecting the operation of the switching apparatus for controlling the direction of flow of current through the motor armature, and means responsive to directional movement of the rotatable member disposed for simultaneous operation with the operating means for the switching apparatus for effecting quick initial changes in the bridge circuit and the direction of flow of current through the motor armature.

6, In a regulating system, in combination, a motor to be controlled, a direct-current source disposed to be connected across the motor armature, a resistor bridge circuit having adjustable resistors in one of the legs thereof connected be tween the direct-current source and the motor armature, switching apparatus disposed for adjusting the adjustable resistors for controllin the flow of current in the bridge circuit to effect a reversal of the motor armature, a member disposed for rotational movement in response to operating conditions of the motor, means respou sive to positional movement of the rotatable member for effecting the operation of the switching apparatus for controlling the direction or flow of current through the motor armature, and means comprising a frictionally actuated switch responsive to directional movement of the rotatable member disposed for simultaneous operation with the operating means for the switching apparatus for eii'ecting quick initial changes in the bridge circuit and the direction of flow of current through the motor armature, the frictionally actuated switch being disposed to maintain the initial changes in the bridge circuit until the di rcctional movement is stopped.

7. In a regulating'system, in combination, a motor to be controlled, 2. generator having an armature disposed to supply current to the motor armature, a pair of opposed field windings for the generator, a sourceof direct current disposed to be connected to the field windings, a pair of resistor circuits each of which is connectedbetween the direct-current source and one of the field windings, a switching apparatus associated with each oi the resistor circuits, a member disposed for rotationalmovement in response to operating conditions of the motor, means responsive to positional movement or the rotatable member for effecting the inverse operation of the switching apparatus for controlling the excitation of the generator, and means responsive to directional movement of the rotatable member disposed for effecting quick initial changes in the resistor circuits to eilectquick initial changes in the excitation of the generator, the quick change ,means being disposed to maintain the initial changes in the field circuits until the directional movement is stopped.

8. In a regulating system, in combination, a motor to be controlled, at direct-current source for supplying the motor, a plurality of circuits connected in circuit relation with the direct-current source for controlling the operation of the motor, means provided in each of the plurality of circuits for controlling the flow of current therein to effect a reversal of the motor, means connected to the motor responsive to operating conditions for effecting the operation of the controlling means, and means operative under predetermined conditions simultaneously with the controlling means for effecting a quick initial change in the flow of current in said plurality of circuits for quickly initiating a change in the operation of the motor.

9. In a regulating system, in combination, a motor the speed and direction of operation of which is to be controlled, a generator connected to supply current to the motor, a pair of opposed field windings for controlling the excitation of the generator, a pair of resistors each of which is disposed to beaadjustably connected in circuit relation with one of the field windings, means disposed for operation to inversely vary the re sistance oi the pair of resistors connected in their respective field winding circuits, a member disposed for movement in response to operatin conditions of the motor to effect the operation of the inversely varying means, and means res onsive to directional movement of said member disposed for effecting quick initial changes in the excitation of the generator.

10. In a regulating system, in combination, a motor the speed and direction of operation of which is to be controlled, a generator connected to supply current to the motor, a pair of opposed field windings for controlling the excitation of the generator, a pair of resistors each of which is disposed to be adiustably connected in circuit relation with one 01 the field windings, means disposed for operation for inversely connecting the pair of resistors in their respective field winding circuits, 9. member disposed for movement in response to operating conditions of the motor to effect the operation of the connecting means, and means responsive to directional movement oi said member disposed for effecting quick initial changes in the excitation of the generator, the quick change means bein disposed to maintain the initial changes in the excitation until the directional movement is stopped.

11. In a regulating system, inicombinatiou, a motor the speed and direction of operation of which is to be controlled, a generator connected to supply current to the'motor, a pair of opposed field windings for controlling the excitation of the generator, '2. pair of resistor circuits each of which is connected in circuit relation with one of the field windings, means disposed for operation toinversely vary the resistance or the pair of resistance circuits, a member disposed for movement in response to operating conditions of the motor to efiect operation of the inversely varying means, and means responsive to directional movement of said member disposed tor selectively effecting quick initial changes in the to inversely vary the resistance of the pair of resistance circuits, a member disposed tor rota-' tional movement in response to operatingaconditions of the motor, means responsive posi-- tional movement 0! the rotatable member for effecting the operation of the inversely varying means, and means responsive to directional movement of the rotatable member disposed for selectively efi'ecting quick initial changes in the resistance of the resistor circuits to efl'ect quick initial changes in the excitation of the generator, the quick change means being disposed to maintain the initial change in the selected field circuit for the duration of the directional movement.

STANLEY J. MIKINA. 

